Adding a short description of the Function class I wrote to help people understand what it does and why.
Adding a short description of the Function class I wrote to help people understand what it does and why.

idaholab/raven,idaholab/raven,joshua-cogliati-inl/raven,idaholab/raven,joshua-cogliati-inl/raven,joshua-cogliati-inl/raven,idaholab/raven,joshua-cogliati-inl/raven,joshua-cogliati-inl/raven,idaholab/raven,joshua-cogliati-inl/raven,idaholab/raven,idaholab/raven,joshua-cogliati-inl/raven